/******************************************************************************
* Copyright (c) 2015-2022 jiangxiaogang<kerndev@foxmail.com>
*
* This file is part of KLite distribution.
*
* KLite is free software, you can redistribute it and/or modify it under
* the MIT Licence.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
******************************************************************************/
#include "kernel.h"
#include "fifo.h"

void fifo_init(fifo_t *fifo, void *buf, uint32_t size)
{
	fifo->buf  = buf;
	fifo->size = size;
	fifo->rp   = 0;
	fifo->wp   = 0;
}

uint32_t fifo_read(fifo_t *fifo, void *buf, uint32_t size)
{
	uint32_t i;
	for(i = 0; i < size; i++)
	{
		if(fifo->rp == fifo->wp)
		{
			break;
		}
		((uint8_t *)buf)[i] = fifo->buf[fifo->rp++];
		if(fifo->rp == fifo->size)
		{
			fifo->rp = 0;
		}
	}
	return i;
}

uint32_t fifo_write(fifo_t *fifo, void *buf, uint32_t size)
{
	uint32_t i;
	uint32_t pos;
	for(i = 0; i < size; i++)
	{
		pos = fifo->wp + 1;
		if(pos == fifo->size)
		{
			pos = 0;
		}
		if(pos == fifo->rp)
		{
			break;
		}
		fifo->buf[fifo->wp] = ((uint8_t *)buf)[i];
		fifo->wp = pos;
	}
	return i;
}

void fifo_clear(fifo_t *fifo)
{
	fifo->wp = 0;
	fifo->rp = 0;
}

uint32_t fifo_get_free(fifo_t *fifo)
{
	if(fifo->rp > fifo->wp)
	{
		return fifo->rp - fifo->wp - 1;
	}
	else
	{
		return fifo->rp + fifo->size - fifo->wp;
	}
}

uint32_t fifo_get_used(fifo_t *fifo)
{
	if(fifo->wp >= fifo->rp)
	{
		return fifo->wp - fifo->rp;
	}
	else
	{
		return fifo->wp + fifo->size - fifo->rp;
	}
}
